Otto Bock Doppelbuchsdrilling

[85lc]

I would like ant information that you can provide about a Otto Bock Doppelbuchsdrilling based upon the Collath tilt & drop action. The rifle appears as a typical Collath Doppelbuchsdrilling and is marked Otto Bock. The calivers are 10.75x65r - 10.75x65r - 32 ga and the 32 ga barrel has a 22 Hornet insert installed and also has a .410 insert. Proof markings and action are shown below. P5010006.jpg P5010007.jpg P5010010.jpg P5010016.jpg

[algmule]

Hello

Below image show bore diameter for the rifle barrels. A plug gauge of 10,41 mm went through at proof but not one of 10,67 mm. So either 10,41 mm or somewhere in between the two.

01-borediameter.jpg

Here is a link to proof marks

https://www.germanguns.com/gun-marks/

No, I do not believe Otto Bock manufactured the thing.

EDIT:
01-bock.jpg

http://www.germanhuntingguns.com/archives/bock-otto/

Peter

[mike ford]

85lc,
I believe Collath made the gun and Otto Bock sold it. Otto Bock mostly sold guns made by others "for the trade". The crown Gs show those barrels were proofed for single projectiles(bullets). The 67/48s show the bore (not groove or bullet) diameter expressed in gauge measurement (it translates to 10.41mm and is consistent with the reported nominal caliber). The imperial eagles show provisional and definitive proof were performed; the crown U shows a View proof was performed after the definitive proofs. The View proofs amount to a detailed inspection, including verification of dimensions. On the shot barrel, the Imperial eagles and crown U have the same meaning as on the rifle barrels. The crown S means the barrel was proofed to fire shot. There is no crown W, so the shot barrel is cylinder bore. The 32 in a circle means it has a standard 32-gauge chamber. The 34 without a circle is the bore diameter ahead of the chamber, also expressed in gauge measurement (translates to 13.08mm). Since the bore diameters of the rifles were expressed in gauge measurement, the gun was made after early 1893, when the 1891 proof law came into effect and before 1912, when the 1911 improvements to the law changed these measurements to millimeters. You stated the shot barrel has a 22Hornet Einstecklauf (EL) installed. Are you sure it is 22Hornet, not 5.6x35R Vierling?The difference is the Hornet has a thicker rim than the 22 WCF (upon which both the later cartridges were formed), to prevent Hornet cartridges from being used in the older rifles. If the gun will no close on a Hornet cartridge, I advise against deepening the rim recess to allow it to close. The world is full of 22 Hornets, but 5.6x35R Vierings are hard to find. Making ammo for the Vierling is not hard. I just thin the rims from the back, deepen the primer pocket with a small rifle primer pocket uniformer. I then load them with normal 22 Hornet dies and shell holder. You should "slug" the barrel, to determine the bullet diameter needed. Mine uses .223"; .224, .222, and .221" are also available. The available .228 jacketed bullets are likely too heavy(long) at 70 grains to stabilize in the EL slower rifling pitch. You should also verify the chamber length in the .410. Older ammo was available in 2" and 2 1/2"shells. Modern 3" shells should not be used in the older chambers. I hope this helps,
Mike

[85lc]

Mike & Peter,

Thank you. I thought that Bock may be the retailer. I read Bock was primarily a taxidermist who marked. I understood trhat many guns Bock sold were made by others (similar to many English gun makers).

However, the rifle is marked "Patent W. Collath" which (to me) indicated it was or could have been made by another maker using the Collath patent.

Without seeing anything that indicated it is a nitro rifle, I believe that it is a blackpowder rifle. Is that correct? The only tilt/drop actions that I know of are the early Chas Lancasters and the Colath. Most were blckpowder though Collath actions transittioned into smokeless (at least shotguns).

The grove diameter is 0.424" (1o.77mm). A 444 Marlin fits the chamber but is too short.

Does the markings indicate anything about bullet weight?

The inserts were made some 30+/- years ago by a well known (in Atlanta) gunsmith (now deceased). He told me that the insert was a 22 Hornet made from a Hornet barrel. I think the .410 may be 2 1/2" (I would measure before trying to shoot it)

I am looking at another Otto Bock marked rifle. Is there any way to tell who made the rifles Bock sold?

[algmule]

Hello

Interestingly the 1892 table does not go smaller than 32 for gauges for shot so they must have used data from the table for projectile for the measurement for gauge 34, which fits Mike's 13,08 mm.

01-proof.jpg

May we have images of the thing assembled?

Peter

[mike ford]

Peter,
Yes, that is what I had to do to find a diameter, I noted the diameters for 32 ga. matched so I guessed those for 34 likely would also.
85lc
People use 9.3x74R cases to make the 65mm case, if they have enough on hand. If they must buy some, they might use brass .410-3" for donor cases. The 9.3 cases have to be fire formed more than once to fully expand them. I used to recommend 7x65R, but experience shows the necks are likely to split if expanded that much and the few that didn't split wound up being shorter than 65mm any way. Since you have 444 cases, I make carpenter bee loads with worn out polishing media for my .410-2 1/2" pistol with them. You could likely load them with shot, as well using 44 shot cups.
Mike